Process of making transparent film material



May 14, 1935. K -rz 2,001,389

PROCESS OF MAKING TRANSPARENT FILM MATERIAL Filed May 14, 1932 Patented May 14, 1935 UNITED STATES PROCESS OF MAKING TRANSPARENT FILM MATERIAL Edouard M. Kratz, Gary,

to Marbo a corporation of Delaware assignments, Chicago, 111.,

Ind., asslgnor, by memo Products Corporation,

Application May 14, 1932, Serial No. 611,329

6 Claims.

This invention relates to a method of makin transparent sheet material having an ornamental design thereon.

Previously, in the production of sheet material, it has been customary to spread a suitable composition evenly upon a smooth surface, allow it to dry or harden, and finally strip the residue off of the smooth surface in the form of a thin sheet. When it has been desired to have ornamental designs appear upon this sheet, it has been accomplished by impressing the desired design upon the smooth surface used to form the sheet. The transparent sheet formed upon such a surface will reproduce the ornamental design, trademark, etc. originally impressed upon the smooth surface. In this manner, it has been possible to make transparent sheets out of gelatine or other material giving them a permanent, ornamental design without using any additional steps in the ordinary process of preparing plain transparent gelatine or other sheets.

This method of producing ornamentation upon transparent sheets has a disadvantage in that any impression made upon the surface upon which the sheet is formed will result in a varying thickness of the finished gelatine sheet. Thus it will be seen that the finished sheet will be materially thinner at certain points in the design thereon than at others, causing the sheet to be very weak at certain places in the design. For example, if the sheet had an average thickness of .001 inch and the design upon the sheet caused a reduction in thickness of .0002 inch, there would be a reduction in strength and thickness of approximately 20% over those portions of the sheet actually occupied by the design.

I have now found a process by which designs may be made upon transparent sheets during the course of their manufacture without materially increasing the expense of the manufacturing operation and without weakening the resulting sheet material.- I

It is, therefore, an object of my invention to produce an ornamental sheet material having superior strength.

It is a further object of my invention to provide a process for producing such an ornamental sheet material.

It isv an additional object of my invention to provide a surface upon which such an ornamental sheet material may be formed.

Other and further important objects of my invention will be evident from the following specification and accompanying drawing.

As shown on the drawing:

Figure 1 is a plan. view of a forming surface V and a transparent sheet produced from said surface, in which the transparent sheet overlaps a portion of the forming surface.

Figure 2 is an edge view of the sheets shown in Figure 1.

On the drawing:

The reference numeral 3 represents generally a sheet of my transparent material and 4 represents a portion of a forming surface upon which 1 such material is made. The sheet 3 and the forming surface 4 are shown overlapping throughout a portion-of their surfaces as at 5. The forming surface 4 may be made from a variety of materials, and may be either flexible or rigid. A baked enamel surface on a flexible fabric base is disclosed in my U. S. Patent No. 1,727,611. Such a surface is preferably formed into a continuous belt and is used in combination with the transparent paper machine described in my Reissue Patent No. 17,854. An ordinary oil cloth may be used for this purpose if desired, and it is also possible to prepare such a belt having a smooth pyroxylin surface.

The surface 4 carries any suitable design which is produced by printing upon said surface with an ink which will dry to form a surface having a different texture from the original. It will be evident that almost any ink will fulfill this requirement, since it would be very exceptional to find any which would dry upon the surface 4 without producing any change whatever in its texture.

It is only necessary that the dried ink be insoluble in the gelatine or other solution used to form the transparent sheet material. However, I prefer to print this design with a fast drying cellulose ester ink which is fiat. By flat I mean an ink which dries to produce a dull surface which contrasts sharply with the original smooth surface 4, which has a glossy finish.

Since the surface 4 is preferably that of a flexible continuous belt such as described in my patent above identified, it will be evident that any suitable design may be printed thereon by means of a roller upon which the design has been 4 engraved. I prefer that the design be printed by an offset method, since this method applies pressure to the surface 4 in a uniform manner, thereby producing no objectionable indentations in said surface. Ordinary printing is not preferred because in this process great pressure is applied to the surface to be printed at all points which are part of the design, and no pressure is applied at portions of the surface which are to be left in their original state. The resulting indentations surface 8, which in the sheet, or surface 4 will be permanent and any transparent sheet material then formed using this surface will be very non-uniform in thickness, thus defeating one of the objects of my invention. An offset, or lithographic method of printing the design upon my surface 4 avoids this difliculty because this method of printing demands a substantially uniform pressure over the entire surface to be printed.

The design upon the surface 4 may be produced by coating entire areas of the surface I with ink as at 8, or by coating in lines, as at 'l or by leaving portions of the original surface untreated as at 6. Of course, a partially coated surface as at 1 may be coated either with lines as shown or dots as in ordinary half tones.

Since the surface 8 is the roughest portion,'the portion of the transparent sheet formed upon this surface will be the most translucent, or opaque, as shown at H; the portion formed on the partly inked surface I will be intermediate in its translucency as at H); and the portion formed on the was untreated, will be transparent as at 9.

It will be understood that I do not limit my invention to a cube or dice design as shown, since it is obvious that an infinite variety of designs may be made following this same principle, the dice design shown being for purposes of Illustration only. It will also be evident that, if I desire, I may use two or more different kinds of ink which produce different degrees of roughness upon drying, to produce various degrees of roughness on the surface of my finished sheet. However, I prefer to use one type of ink and produce the various degrees of roughness, or translucency, by the use of lines or dots, of varying widths as explained above, since this is less expensive and troublesome than the use of. several inks. The transparent sheet may be formed on this surface in accord with the disclosures in my above identified patent, using a solution of gelatine such as is disclosed in my copendlng application Serial No. 10,962. Other suitable base materials for forming sheet material on a surface such as described herein include casein in the form of a solution of an alkali metal caseinate and formaldehyde, or any film forming base that sets or hardens to a dense sheet.

When this invention is used in connection with the continuous belt surface disclosed in one of my patents above identified, it has special advantages over previously known methods of producing designs upon the carrier web by embossing. When such a surface is embossed it must be pressed at high temperatures and pressure upon a plate or roll carrying the desired design. Any such treatment of the jection since the belt fabric base and the high temperature and pressure tend to force this fabric to the surface destroying its original high polish and causing a web or fabric appearance in the finished transparent sheet material. My'method of making the design upon the belt or other surface 4 avoids this difilculty since the design isapplied at room temthe printing operation willihavei oi-gletrimental effect upon the belt.

. f .f j

Thus it will be seen that have devised'a method of producing designs on atransparent sheet "ma terial during the perature and the mom 'tar'ypreasurereduired in carrier belt is open to obis made upon a web or.

course of its manufacture which has many advantages over previously known methods and which produces a very uniform product.

I am aware that many changes may be made and numerous details may be varied through a wide range without. departing from the principles of this invention, and I, therefore, do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

I claim as my invention:

1. The method of forming sheet material having an ornamental design, which comprises printing upon a smooth surface by an offset process to form designed portions of a different finish from the original finish of said surface without indenting said surface; coating a solution capable of forming a sheet material upon said surface, and stripping the resulting sheet material off -of said surface with said designed portions reproduced on said sheet material, the finish remaining on said smooth surface after the stripping step.

2. The method of forming sheet material having an ornamental design which comprises forming designs upon a smooth surface by an offset printing process with an ink which will dry to form a surface having a different texture from the original surface; coating a, solution containing gelatine thereon, and stripping the resulting sheet material off of said surface, said ink being insoluble in said solution, said inkremaining entirely upon said smooth surface-after said stripping of the resulting coating off said surface,

3. The method of forming sheet, material having an ornamental design thereon-, wh'ich comprises forming designs upon a smooth surface by an offset printing process with anfink which will dry to form a surface of dull texture; coating said surface with a'solutionadapted to dry to containing gelatine thereon, allowing said solution to dry and'stripping the resulting coating off of said surface, said ink being insoluble in;said gelatine solution, and remaining intact on said smooth surface after said stripping step.

5. The method of forming transparent sheet material having a. design thereon, which comprises forming designs on'a'smooth surface by an offset printing process with a fiat nitrocellulose ink; coating the designed surface with a solution containing gelatine; allowing said solution to dry, and stripping the resulting coating off of said surface, said ink being insolublein said gelatine solution, and remaining intact on said's'mooth surface after said stripping step.

6. The methodvof :formin'g transparent material having a design thereon, which comprises forming designs on a smooth surface by a. litho- {graphic process, coating the designed surface with a film formingsolutiomallowing said solution to -;dr and stripping the resulting coating on of said surface leavingthe design on said surface intact.

EDOUARD M. KRATZ. 

